well basically it starts up fine and i can actually take off with it. But after a couple of minutes i can hear the power drop like its just above a throttle. When i land the motor is still running but very hot. I have tried to run it richer but it still seems to have to power. I have also done the trick where you hold the nose up to see if power is lost and that doesnt seem to be a problem. Is there anyway to clean the engine up? I have it mostly taken apart and there is alot of black residue inside but I have not seen any metal or anything. I am also running a hot glow plug which is suppose to be able to let you run at a richer setting. and I use 10% fuel. My brother also flies with me and he uses the same fuel and glow plug in his o.s. max 40 la.